CLD-R sample exam #2, question #11

[1984]

I was failed to know 12 out of the 40 which is my fault, but I believe this question was not testing my labview skills but my abilities to make a lucky guess. So yeap, I guess I can blame this question as this was the decision making one over pass/fail.

Option B and C ARE unreliable as we chaining the variables up to the error cluster, but both A and B executes reliably so I dont see how should I differentiate between them.

I understand that A executes them in an order but again, it was not a requirement. If this is considered as a decision making factor then two parallel for loops counting to 4 are unreliable as we can't predict which one finishes first. Yes we CAN'T predict that, but the code is still executes reliably.

In this topic nobody started to a sentence like "Its obvious that A is the right answer, and the reason is...", but everybody tried to guess the reason based on that they know that A is the right one, which is just the indication of how unclear this question is.

[Jacobson-ni]

I will start this by saying I do not think that this is a particularly good question.  I am also not part of NI's certification team so this is all my opinion.

---

@1984 wrote:

Option B and C ARE unreliable as we chaining the variables up to the error cluster

---

Most people tend to agree on this so I won't go over that.  What people do not agree on is whether answer A or D is the better answer so I will throw in my two cents.

The first definition of reliable in Merriam-Webster that is not self-referencial is, "giving the same result on successive trials".  But even given the same inputs, D might not have the same result across multiple trials,  I would argue then that D is not reliable.

[1984]

In the past 12 years I have developped and deployed unreliable codes like this in about 10 different countries.

If this is unreliable then NI should start reviewing its own VIs as there are numerous VIs shipped with LabVIEW has solutions like this.

[crossrulz]

---

1984 wrote:

If this is unreliable then NI should start reviewing its own VIs as there are numerous VIs shipped with LabVIEW has solutions like this.

---

There is A LOT of code inside of LabVIEW that should be fixed.  We all know that.  That's what happens when you have 30 years of code base being built up and going back and changing things a VERY risky.

As far as this question is involved, remember the main criteria: the BEST answer.  What does D gain you over A?  Nothing.  What does A gain you over D?  Guaranteed order of execution!  Therefore A is better than D.

If you think the CLD-R is rough, just wait until you get a try at the CLA-R.  The questions are so that they actually expect a CLA to get an 80%, 70% is a fail.  Why?  Because there are SO many things they want to try to cover that not everybody has done.  So expecting a CLA to know 80% of LabVIEW is what they put as the bar.

Besides, nobody should be taking the CLD-R and CLA-R.  They should be working up their Recertification By Points!

[26588360]

Hi,

I have already mentions that A is correct answer and not even D. when someone is  already CLD certified, NI expects they alredy following statndars, so when Error occured and passed to this code, shut down condtion will not be executed because of Error. so D can't be the answere. In case of A, it doesn't check the error condtion and executes the code which is need to be executed for shut down code.  here oder of closing is not playing any role.

So A is correct solution.

[1984]

Yeah, you metioned something about reliability, but I dont understand what you are talking about as the shutdown will happen in both A and D. The error in terminals of the variables is a dont care as the error was cleared.

[1984]

In my opinion if the guaranteed order of execution is not in the requirement then it is simply a personal preference and not benchmarking the code. The answer would be obviously (A) if it was having any reference that the code needs to shut down the variables in order.

I'd like start collecting points by submitting this task to either the CLDR or the CLAR list of questions:

It is a tricky question as most of the candidates would mark (D) as the correct answer, but (A) is the right one. What does A gain you over D?  Guaranteed order of execution!  Therefore A is better than D.

[jcarmody]

never mind...

[crossrulz]

---

@1984 wrote:

In my opinion if the guaranteed order of execution is not in the requirement then it is simply a personal preference and not benchmarking the code. The answer would be obviously (A) if it was having any reference that the code needs to shut down the variables in order.

---

Dealing with hardware is completely different than dealing with math.  In the systems I deal with, this order is very important.  Yes, this question is crap.  It is taking ideas that are more than just developing LabVIEW software.  It is taking in ideas of hardware and system interfaces as well.  And since LabVIEW was originally designed for interfacing with hardware, there is an assumption that the CLD will know about best practices in hardware interfacing.

[JÞB]

---

@1984 wrote:

In the past 12 years I have developped and deployed unreliable codes like this in about 10 different countries.

If this is unreliable then NI should start reviewing its own VIs as there are numerous VIs shipped with LabVIEW has solutions like this.

---

Hey, lets assume this is a control system for (Why not?) a 250kWatt weather radar

1. Stop the pulse modulator
2. shut down the RF Source
3. Remove power to the Klystron's magnet 

Trust me, you want them to happen in that order.  with code shown as drawn above, there is a possibility to remove the magnetic field first.  That would dump a 60kV 12A pulse through the klystron with no field to focus the beam.  At which point a 70 pound klystron is going to impolitely install a new hole in the building's roof.

Frankly, I despise that question as none of the distractors takes into account a failure in a predicated step of shutdown.